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arXiv 2025年

作者： Yuan, Eric C.-Y. Liu, Yunsheng Chen, Junmin Zhong, Peichen Raja, Sanjeev Kreiman, Tobias Vargas, Santiago Xu, Wenbin Head-Gordon, Martin Yang, Chao Blau, Samuel M. Cheng, Bingqing Krishnapriyan, Aditi Head-Gordon, Teresa Kenneth S. Pitzer Theory Center Department of Chemistry United States Department of Chemical and Biomolecular Engineering United States Electrical Engineering and Computer Science United States Bakar Institute of Digital Materials for the Planet University of California BerkeleyCA94720 United States Chemical Sciences Division United States Applied Mathematics and Computational Research Division United States Energy Technologies Area United States National Energy Research Scientific Computing Center Lawrence Berkeley National Laboratory BerkeleyCA94720 United States

Given the power of large language and large vision models, it is of profound and fundamental interest to ask if a foundational model based on data and parameter scaling laws and pre-training strategies is possible for learned simulations of chemistry and materials. The scaling of large and diverse datasets and highly expressive architectures for chemical and materials sciences should result in a foundation model that is more efficient and broadly transferable, robust to out-of-distribution challenges, and easily fine-tuned to a variety of downstream observables, when compared to specific training from scratch on targeted applications in atomistic simulation. In this Perspective we aim to cover the rapidly advancing field of machine learned interatomic potentials (MLIP), and to illustrate a path to create chemistry and materials MLIP foundation models at larger scale. © 2025, CC BY-SA.

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Response surface models for hydrate prediction: Deterministic and probabilistic applications

Response surface models for hydrate prediction: Deterministi...

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12th International Conference on Multiphase Production Technology '05

作者： Averbuch, D. Gainville, M. Pierchon, A. Dejean, J.-P. Applied Mechanics Division Technology IFP France Computer Science and Applied Mathematics Division IFP France

ISBN: (纸本)1855980649

During the design phases of a Deep Offshore field development, a major issue in Flow Assurance is the prevention of Hydrates formation in the flowlines and risers. After designing the system, numerous multiphase flow and transient cool-down simulations are required, to account for different situations corresponding to several input parameters. This paper shows how to build efficiently Response Surfaces Models (RSM), which are simple mathematical models, accurately describing the critical time of hydrate formation, as a function of the input parameters, over a wide range of variation covering their variability. The obtained RSM can provide useful information for several applications such as sensitivity studies, in order to exhibit the most important input parameters, to reduce the calculation number, or to take into account uncertainty in the parameters. © BHR Group 2005 Multiphase Production Technology 12.

关键词： Hydrates

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High Hospitalization Rates and Risk Factors Among Frail Patients With Cirrhosis: A 10-year Population-based Cohort Study

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Clinical Gastroenterology and Hepatology 2025年第7期23卷 1152-1163页

作者： Hasjim, Bima J. Mohammadi, Mohsen Balbale, Salva N. Paukner, Mitchell Banea, Therese Shi, Haoyan Furmanchuk, Al'ona VanWagner, Lisa B. Zhao, Lihui Duarte-Rojo, Andres Doll, Julianna Mehrotra, Sanjay Ladner, Daniela P. Northwestern University Transplant Outcomes Research Collaborative (NUTORC) Comprehensive Transplant Center (CTC) Northwestern University Chicago Illinois United States Center for Engineering and Health McCormick School of Engineering and Applied Science Northwestern University Chicago Illinois United States Department of Industrial Engineering and Management Sciences McCormick School of Engineering Northwestern University Evanston IL United States Division of Gastroenterology and Hepatology Department of Medicine Northwestern University Feinberg School of Medicine Chicago Illinois United States Center for Health Services and Outcomes Research Institute of Public Health and Medicine & Northwestern Quality Improvement Research & Education in Surgery (NQUIRES) Department of Surgery Northwestern University Feinberg School of Medicine Chicago Illinois United States Center of Innovation for Complex Chronic Healthcare (CINCCH) Edward Hines Jr. VA Hospital Hines IL United States Division of Biostatistics Department of Preventive Medicine Northwestern University Feinberg School of Medicine Chicago Illinois United States Department of Mathematics Northwestern University Evanston IL United States Department of Computer Science McCormick School of Engineering Northwestern University Evanston IL United States Department of General Internal Medicine Feinberg School of Medicine Northwestern University Chicago Illinois United States Division of Digestive and Liver Diseases Department of Medicine University of Texas Southwestern Medical Center Dallas Texas United States Division of Transplantation Department of Surgery Northwestern University Feinberg School of Medicine Chicago Illinois United States

Background & Aims: Cirrhosis-related inpatient hospitalizations have increased dramatically over the past decade. We used a longitudinal dataset capturing a large metropolitan area in the United States from 2011 to 2021 to evaluate contemporary hospitalization rates and risk factors among frail patients with cirrhosis. Methods: We conducted a retrospective, longitudinal cohort study using the Chicago Area Patient-Centered Outcomes Research Network (CAPriCORN) database, an electronic health record repository that aggregates de-duplicated data across 7 health care systems in the Chicago metropolitan area, from 2011 to 2021. The primary outcome of our study was the rate of hospitalization encounters. Frailty was defined by the Hospital Frailty Risk Score. Hospitalization rates were reported per 100 patients per year, and a multivariable logistic regression analysis identified predictors of annual hospitalization probability. Results: During the study period, of 36,971 patients, 16,265 patients (44%) were hospitalized (compensated, 18.4%;decompensated, 81.6%). Hospitalization rates were highest in patients with decompensated cirrhosis, reaching nearly 77.3 hospitalizations/100 patients per year. Hospitalization rates among patients with compensated cirrhosis were also high (14.2 vs 77.3 hospitalization/100 patients per year), with odds of annual hospitalization 3 times (odds ratio, 3.1;95% confidence interval, 2.9-3.4) as high among compensated patients with intermediate frailty and 5 times (odds ratio, 5.2;95% confidence interval, 4.5-6.0) as high among those with severe frailty (compared with compensated patients with low frailty). Conclusion: Compensated and decompensated cirrhosis patients with intermediate to severe frailty face a substantially increased odds of annual hospitalizations compared with those with low frailty. Future work should focus on targeted interventions to incorporate routine frailty screenings into cirrhosis care and to ultimately minimize high

关键词： Cirrhosis Frailty Hospitalizations

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Absolute change pivot rule for the simplex algorithm

Absolute change pivot rule for the simplex algorithm

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International MultiConference of Engineers and computer Scientists, IMECS 2014

作者： Chankong, Kittiphong Intiyot, Boonyarit Sinapiromsaran, Krung Applied Mathematics and Computational Science Program Department of Mathematics and Computer Science Faculty of Science Chulalongkorn University Bangkok Thailand

ISBN: (纸本)9789881925336

The simplex algorithm is a widely used method for solving a linear programming problem (LP) which is first presented by George B. Dantzig. One of the important steps of the simplex algorithm is applying an appropriate pivot rule, the rule to select the entering variable. An effective pivot rule can lead to the optimal solution of LP with the small number of iterations. In a minimization problem, Dantzig's pivot rule selects an entering variable corresponding to the most negative reduced cost. The concept is to have the maximum improvement in the objective value per unit step of the entering variable. However, in some problems, Dantzig's rule may visit a large number of extreme points before reaching the optimal solution. In this paper, we propose a pivot rule that could reduce the number of such iterations over the Dantzig's pivot rule. The idea is to have the maximum improvement in the objective value function by trying to block a leaving variable that makes a little change in the objective function value as much as possible. Then we test and compare the efficacy of this rule with Dantzig' original rule.

关键词： Linear programming

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The differential geometry of shape from shading: Biology reveals curvature structure

The differential geometry of shape from shading: Biology rev...

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2012 IEEE computer Society Conference on computer Vision and Pattern Recognition Workshops, CVPRW 2012

作者： Kunsberg, Benjamin Zucker, Steven W. Applied Mathematics Program Yale University United States Departments of Computer Science and Applied Mathematics Yale University United States

ISBN: (纸本)9781467316118

Shape from shading is a classical inverse problem in computer vision. We introduce a novel mathematical formulation for calculating local surface shape based on covariant derivatives, rather than the customary integral minimization or P.D.E approaches. Motivated by neurobiology, we introduce the shading flow field (the tangent map to the image isophotes) between the image and the surface levels. Just as in the perceptual organization of texture, we use the parallel transport of our shading flow field to move the isophote field at different points on the unknown surface to a single point, amassing restrictions on our surface curvatures. Under simplifying assumptions we solve exactly for the light source/surface pairs needed for a local image patch to have a given shading flow. The magnitude of the brightness gradient then restricts this family to a single light source and surface estimate pair, up to the concave/convex ambiguity and an additional elliptical/saddle ambiguity. Example calculations illustrate our approach. © 2012 IEEE.

关键词： Flow fields

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Colouring of COVID-19 Affected Region Based on Fuzzy Directed Graphs

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computers, Materials & Continua 2021年第7期68卷 1219-1233页

作者： Rupkumar Mahapatra Sovan Samanta Madhumangal Pal Jeong-Gon Lee Shah Khalid Khan Usman Naseem Robin Singh Bhadoria Department of Applied Mathematics with Oceanology and Computer Programming Vidyasagar UniversityMidnapore721102India Department of Mathematics Tamralipta MahavidyalayaTamluk721636India Division of Applied Mathematics Wonkwang UniversityIksan-SiJeonbuk54538Korea School of Engineering RMIT UniversityMelbourne3001Australia School of Computer Science University of Sydney Sydney2006Australia Department of Computer Science&Engineering Birla Institute of Applied Sciences(BIAS)BhimtalUttarakhand263136India

Graph colouring is the system of assigning a colour to each vertex of a *** is done in such a way that adjacent vertices do not have equal *** is fundamental in graph *** is often used to solve real-world problems like traffic light signalling,map colouring,scheduling,***,social networks are prevalent systems in our ***,the users are considered as vertices,and their connections/interactions are taken as *** users follow other popular users’profiles in these networks,and some don’t,but those non-followers are connected directly to the popular *** means,along with traditional relationship(information flowing),there is another relation among *** depends on the domination of the relationship between the *** type of situation can be modelled as a directed fuzzy *** the colouring of fuzzy graph theory,edge membership plays a vital *** membership is a representation of flowing information between end nodes of the *** from the communication relationship,there may be some other factors like domination in *** influence of power is captured *** this article,the colouring of directed fuzzy graphs is defined based on the influence of *** with this,the chromatic number and strong chromatic number are provided,and related properties are *** application regarding COVID-19 infection is presented using the colouring of directed fuzzy graphs.

关键词： Graph colouring chromatic index directed fuzzy graphs

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A NEAR-OPTIMAL MANHATTAN CHANNEL ROUTER FOR A CLASS OF NETS WITH THE SHIFT-RIGHT-ONE PATTERN

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applied mathematics LETTERS 1993年第6期6卷 65-69页

作者： TUAN, TC Institute of Applied Mathematics (Computer Science Program) National Sun Yat-sen University Kaohsiung Taiwan 80424 People's Republic of China

The Manhattan channel routing problem of providing a one-to-one rectilinear wire connection (horizontal segments on one layer, while vertical segments are on the other) between two sets of terminals which lie on two horizontal lines, with the smallest width, is NP-hard. In this paper, it is studied for m consecutive shift-right-one nets, and a near-optimal router which produces a layout with width at most 2 more than the theoretical lower bound given in [1] is presented.

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PARALLEL ALGORITHMS FOR THE DIRECT SOLUTION OF FINITE-ELEMENT EQUATIONS ON A DISTRIBUTED MEMORY computer 2nd

PARALLEL ALGORITHMS FOR THE DIRECT SOLUTION OF FINITE-ELEMEN...

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2ND EUROPEAN CONF ON DISTRIBUTED MEMORY COMPUTING ( EDMCC2 )

作者： ZONE, O KEUNINGS, R ROOSE, D Division of Applied Mechanics Université Catholique de Louvain Belgium Department of Computer Science and Applied Mathematics Katholiek Universiteit Leuven Belgium

ISBN: (纸本)3540539514

This work constitutes the first phase of a long-term project, namely the efficient implementation of direct solution methods for complex finite element problems on distributed memory parallel computers. Although for the most part limited to the one-dimensional case, our results demonstrate the potential of parallel computing for this class of problems. It is found that the efficiency of the proposed algorithms increases as the problem size increases. We have shown that a performance model can be developed and used for predicting with good accuracy the behavior of the proposed algorithms. Finally, our preliminary results for the two-dimensional case are encouraging. Work is underway to further generalize the present approach to complex multi-dimensional problems. © Springer-Verlag Berlin Heidelberg 1991.

关键词： One dimensional

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Emergent dimer-model topological order and quasi-particle excitations in liquid crystals: combinatorial vortex lattices

arXiv

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arXiv 2025年

作者： Meng, Cuiling Wu, Jin-Sheng Kos, Žiga Dunkel, Jörn Nisoli, Cristiano Smalyukh, Ivan I. Department of Physics and Chemical Physics Program University of Colorado BoulderCO80309 United States Hiroshima University Hiroshima Higashihiroshima Japan Department of Mathematics Massachusetts Institute of Technology CambridgeMA02139 United States Faculty of Mathematics and Physics University of Ljubljana Ljubljana Slovenia Department of Condensed Matter Physics Jožef Stefan Institute Ljubljana Slovenia Theoretical Division Physics of Condensed Matter and Complex Systems Center For Nonlinear Studies Los Alamos National Laboratory Los AlamosNM87545 United States Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program University of Colorado BoulderCO80309 United States Renewable and Sustainable Energy Institute National Renewable Energy Laboratory University of Colorado BoulderCO80309 United States

Liquid crystals have proven to provide a versatile experimental and theoretical platform for studying topological objects such as vortices, skyrmions, and hopfions. In parallel, in hard condensed matter physics, the concept of topological phases and topological order has been introduced in the context of spin liquids to investigate emergent phenomena like quantum Hall effects and high-temperature superconductivity. Here, we bridge these two seemingly disparate perspectives on topology in physics. Combining experiments and simulations, we show how topological defects in liquid crystals can be used as versatile building blocks to create complex, highly degenerate topological phases, which we refer to as ‘Combinatorial Vortex Lattices’ (CVLs). CVLs exhibit extensive residual entropy and support locally stable quasi-particle excitations in the form of charge-conserving topological monopoles, which can act as mobile information carriers and be linked via Dirac strings. CLVs can be rewritten and reconfigured on demand, endowed with various symmetries, and modified through laser-induced topological surgery — an essential capability for information storage and retrieval. We demonstrate experimentally the realization, stability, and precise optical manipulation of CVLs, thus opening new avenues for understanding and technologically exploiting higher-hierarchy topology in liquid crystals and other ordered media. Copyright © 2025, The Authors. All rights reserved.

关键词： Laser surgery

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SPINET: a parallel computing approach to spine simulations

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Scientific programming 1996年第1期5卷 15-15页

作者： Kropf, Peter G. Lederer, Edgar F.A. Steffen, Thomas Guggisberg, Karl Schneider, Jean-Guy Schwab, Peter Department of Computer Science Laval University Quebec City Canada Institute of Computer Science University of Basel Switzerland Orthopaedic Research Laboratory Division of Orthopaedic Surgery McGill University Montreal Canada Institute of Computer Science and Applied Mathematics University of Berne Switzerland

Research in scientitic programming enables us to realize more and more complex applications, and on the other hand, application-driven demands on computing methods and power are continuously growing. Therefore, interdisciplinary approaches become more widely used. The interdisciplinary SPINET project presented in this article applies modern scientific computing tools to biomechanical simulations: parallel computing and symbolic and modern functional programming. The target application is the human spine. Simulations of the spine help us to investigate and better understand the mechanisms of back pain and spinal injury. Two approaches have been used: the first uses the finite element method for high-performance simulations of static biomechanical models, and the second generates a simulation developmenttool for experimenting with different dynamic models. A finite element program for static analysis has been parallelized for the MUSIC machine. To solve the sparse system of linear equations, a conjugate gradient solver (iterative method) and a frontal solver (direct method) have been implemented. The preprocessor required for the frontal solver is written in the modern functional programming language SML, the solver itself in C, thus exploiting the characteristic advantages of both functional and imperative programming. The speedup analysis of both solvers show very satisfactory results for this irregular problem. A mixed symbolic-numeric environment for rigid body system simulations is presented. It automatically generates C code from a problem specification expressed by the Lagrange formalism using Maple.

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